It is well known that motor vehicles may be equipped with devices for preventing unauthorized use. For this purpose, some motor vehicles may have a mechanical locking device for the steering system.
In this connection, a steering system is mechanically locked and unlocked using the ignition key, which actuates a cam (an eccentric) and a spring-loaded slide bar. The slide bar is moved axially by turning the ignition key in the ignition lock, on whose end an eccentric disk is seated. A spring continuously presses this slide bar into the locked end position. In turn, a nose on the slide bar moves a locking gear rim into gear teeth of the steering gear shaft (a pitman arm shaft). Depending on the end position of the slide bar, the steering system is either freely rotatable or locked. If the ignition key is pulled out, the steering system is locked. This ensures that the key cannot be mistakenly pulled out in the unlocked position.
If the steering system is to be unlocked, the key must first be slid into the steering lock. After the key is inserted and turned, the eccentric disk presses the slide bar out of its spring-actuated, locked end position. The pitman arm shaft is released and is, therefore, freely rotatable. The steering system is locked by pulling the ignition key out of the ignition lock. In this way, the eccentric disk releases the slide bar, which is slid into the locked end position by a spring.
Since such steering locking systems are operated in a purely mechanical manner, and also need a key having a conventional bit in order to be operated, they may not be integrable into an electronic driving-authorization system with code input.